Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Prenylated-coumarins from Gmelina arborea and evaluation for neurotrophic activity

A MeOH extract of the stem of Gmelina arborea Roxb. ex Sm. (Lamiaceae) exhibited neurite outgrowth-promoting activity in NGF-mediated PC12 cells. Bioassay-guided fractionation resulted in the isolation of eight previously undescribed prenylated coumarin compounds along with nine known compounds. Structural elucidation of these compounds was accomplished by analysis of extensive spectroscopic data, comparison with the literature, and chemical reactions. It was the first time to find prenylated coumarin compounds from G. arborea. Among the isolated compounds, N-methylflindersine and artanin showed neurite outgrowth-promoting activity in NGF-mediated PC12 cells.

Anchietins A-E: 30-norfriedelane-type triterpenes from Anchietea pyrifolia

Five undescribed norfriedelane triterpenoids, anchietins A-E, along with three known norfriedelane triterpenoids, 21β-hydroxycaloncobalactone, and welwitschiilactones B and C, were isolated from the vine of Anchietia pyrifolia. The compounds were characterized by spectroscopic and crystallographic methods, including 2D NMR spectroscopy and single crystal X-ray crystallography. The isolated compounds were evaluated for the cytotoxic activity against HeLa and HL60 cells and for the inhibitory activity against lipopolysaccharide-induced NO production. Further, inhibitory effects on the inducible nitric oxide synthase mRNA expression levels were also assessed.

Transcriptome analysis of PC12 cells reveals that trans-banglene upregulates RT1-CE1 and downregulates abca1 in the neurotrophic pathway

Trans(t)-banglene and cis(c)-banglene possess neurotrophin-like activity in rat neurons. However, the molecular mechanisms underlying t-banglene-induced neurotrophic activity in rat and human neurons remain unclear. Here, we performed transcriptome analysis in PC12 cells, a rat adrenal gland pheochromocytoma cell line treated with t-banglene, using comprehensive RNA sequencing. The differentially expressed gene analysis of the sequencing data revealed that the expression of RT1 class I, locus CE1 (RT1-CE1) was upregulated, and that of ATP binding cassette subfamily A member 1 (abca1), myosin light chain 6, and hippocampus abundant transcript 1 was downregulated in t-banglene-treated PC12 cells, with statistically significant differences. We also confirmed the RT1-CE1 upregulation and abca1 downregulation in t-banglene-treated PC12 cells by reverse transcription quantitative real-time polymerase chain reaction. RT1-CEl is a major histocompatibility complex class I (MHCI) protein. ABCAl is a major cholesterol transporter that regulates efflux of intracellular cholesterol and phospholipids. Thus, our results suggest an exciting link between MHCI, cholesterol regulation, and neural development.

Vietnamese Dalbergia tonkinensis: A Promising Source of Mono- and Bifunctional Vasodilators

Hypertension is a risk factor for cardiovascular diseases, which are the main cause of morbidity and mortality in the world. In the search for new molecules capable of targeting K_Ca1.1 and Ca_V1.2 channels, the expression of which is altered in hypertension, the in vitro vascular effects of a series of flavonoids extracted from the heartwoods, roots, and leaves of Dalbergia tonkinensis Prain, widely used in traditional medicine, were assessed. Rat aorta rings, tail artery myocytes, and docking and molecular dynamics simulations were used to analyse their effect on these channels. Formononetin, orobol, pinocembrin, and biochanin A showed a marked myorelaxant activity, particularly in rings stimulated by moderate rather than high KCl concentrations. Ba²⁺ currents through Ca_V1.2 channels (I_Ba1.2) were blocked in a concentration-dependent manner by sativanone, 3′-O-methylviolanone, pinocembrin, and biochanin A, while it was stimulated by ambocin. Sativanone, dalsissooside, and eriodictyol inhibited, while tectorigenin 7-O-[β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside], ambocin, butin, and biochanin A increased I_KCa1.1. In silico analyses showed that biochanin A, sativanone, and pinocembrin bound with high affinity in target-sensing regions of both channels, providing insight into their potential mechanism of action. In conclusion, Dalbergia tonkinensis is a valuable source of mono- and bifunctional, vasoactive scaffolds for the development of novel antihypertensive drugs.

Four Clerodane Diterpenoids From Ptychopetalum Olacoides

A phytochemical component investigation of the bark of Ptychopetalum olacoides led to the isolation of 4 new clerodane-type diterpenoids, namely, ptycholide V (1), 7α,20-dihydroxykolavelool (2), ptycholide VI (3), and ptycholide VII (4). Their structures were elucidated by extensive spectroscopic data and comparison of NMR data with that obtained for known compounds.

[Synthetic Studies on Small Molecule Natural Products with Neurotrophic Activity]

Neurotrophic factors have been shown to potentially be beneficial for the treatment of neurodegenerative diseases such as Alzheimer's disease, because endogenous neurotrophic factors (NGF, BDNF) have been recognized to play critical roles in the promotion of neurogenesis, differentiation, and neuroprotection throughout the development of the central nervous system. However, high-molecular-weight proteins are unable to cross the blood-brain barrier and are easily decomposed under physiological conditions. Thus, small molecules that can mimic the functions of neurotrophic factors are promising alternatives for the treatment of neurodegenerative disease. Since 1990, the author has been involved in searching for natural products with typical neurotrophic properties that can cause neurogenesis, enhance neurite outgrowth, and protect against neuronal death by using three cellular systems (PC12, rat cortical neurons, and MEB5 cells). Through these research activities on neurotrophic natural products, the author has tried to induce a paradigm shift from the discipline of natural products chemistry to science disciplines. This review focuses on our independent synthetic studies of the neurotrophic natural products discovered in the plants. The following synthetic elaborations are described: syntheses of dimeric isocuparane-type sesquiterpenes mastigophorenes A and B, macrocyclic bis-bibenzyls plagiochins A-D and cavicularin through a Pd-catalyzed Stille-Kelly reaction; the formal synthesis of merrilactone A and jiadifenin, which are seco-prezizaane-type sesquiterpenes, through intramolecular Pd-catalyzed Mizoroki-Heck and Tsuji-Trost reactions; and finally the first enantioselective synthesis of neovibsanin B, a vibsane-type diterpene, through a Pd-catalyzed cyclic carbopalladation-carbonyl tandem reaction.

Diagnostic performance of fractional flow reserve derived from computed tomography in the stented coronary arteries

Background

The current system of HeartFlow fractional flow reserve derived from computed tomography (FFRCT) is not available for stented coronary arteries. However, the latest version of HeartFlow FFRCT has the potential of rendering an accurate assessment for stented coronary arteries.

Objectives

To evaluate the feasibility of FFRCT for the stented coronary arteries.

Methods

We retrospectively enrolled patients with a history of coronary stent implantation who underwent invasive fractional flow reserve (FFR) for the stented coronary arteries within 3 months after coronary computed tomographic angiography (cCTA). As a subgroup analysis, we analyzed optical coherence tomography (OCT) images in patients who underwent OCT for stented vessels. OCT was performed as a part of the Kobe University Hospital OCT registry, which is a single-centre registry of consecutive patients who underwent OCT for the coronary arteries. The diagnostic performance of HeartFlow FFRCT for stented vessels was evaluated by comparing with that of cCTA alone. Minimum lumen area (MLA) within stent segments derived from cCTA was also compared with MLA derived from optical coherence tomography (OCT).

Results

A total of 30 vessels in 23 patients were studied. The diagnostic accuracy, sensitivity, specificity, positive and negative predictive value of FFRCT for myocardial ischemia using invasive FFR as a reference standard was 73.3%, 88.9%, 67.7%, 53.3% and 93.3%, respectively. FFRCT provided superior diagnostic performance than cCTA alone (p=0.016). FFRCT was significantly correlated with the invasive FFR (r=0.620, p<0.001), and Bland-Altman plot showed a mean bias of −0.041 with 95% limit of agreement of −0.173 to 0.092 (Figure 1). Among a total of 30 studied vessels, OCT was available for 25 vessels. MLA derived from cCTA correlated significantly with that derived from OCT (r=0.695, p<0.001), and Bland-Altman plot showed a mean bias of −0.32 mm2 with 95% limit of agreement of −2.89 to 2.25 mm2 (Figure 2).

Conclusions

The latest version of the HeartFlow FFRCT has the potential to be available for stented coronary arteries. Further investigation is required to elaborate our results.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

A Concise Total Synthesis of Dehydroantofine and Its Antimalarial Activity against Chloroquine-Resistant Plasmodium falciparum

The total synthesis of dehydroantofine was achieved by employing a novel, regioselective, azahetero Diels-Alder reaction of easily accessible 3,5-dichloro-2H-1,4-oxazin-2-one with 14 a as a key step. Furthermore, it is demonstrated that dehydroantofine is a promising candidate as a new antimalarial agent in a biological assay with chloroquine-resistant Plasmodium falciparum.

Potential relationship between high wall shear stress and plaque rupture that cause acute coronary syndrome: insights from optical coherence tomography based computational fluid dynamic simulation

Background

The direct relationship between plaque rupture (PR) that cause acute coronary syndrome (ACS) and wall shear stress (WSS) remains uncertain.

Methods

From the Kobe University ACS-OCT registry, one hundred ACS patients whose culprit lesions had PR documented by optical coherence tomography (OCT) were enrolled. Lesion-specific 3D coronary artery models were created using OCT data. Specifically, at the ruptured portion, the tracing of the luminal edge of the residual fibrous cap was smoothly extrapolated to reconstruct the luminal contour before PR. Then, WSS was computed from computational fluid dynamics (CFD) analysis by a single core laboratory. Relationships between WSS and the location of PR were assessed with 1) longitudinal 3-mm segmental analysis and 2) circumferential analysis. In the longitudinal segmental analysis, each culprit lesion was subdivided into five 3-mm segments with respect to the minimum lumen area (MLA) location at the centered segment (Figure. 1). In the circumferential analysis, we measured WSS values at five points from PR site and non-PR site on the cross-sections with PR. Also, each ruptured plaque was categorized into the lateral type PR (L-PR), central type PR (C-PR), and others according to the relation between the site of tearing and the cavity (Figure. 2).

Results

In the longitudinal 3-mm segmental analysis, the incidences of PR at upstream (UP1 and 2), MLA, and downstream (DN1 and 2) were 45%, 40%, and 15%, respectively. The highest average WSS was located in UP1 in the upstream PR (UP1: 15.5 (10.4–26.3) vs. others: 6.8 (3.3–14.7) Pa, p<0.001) and MLA segment in the MLA PR (MLA: 18.8 (6.0–34.3) vs. others: 6.5 (3.1–11.8) Pa, p<0.001), and the second highest WSS was located at DN1 in the downstream PR (DN1: 5.8 (3.7–11.5) vs. others: 5.5 (3.7–16.5) Pa, p=0.035). In the circumferential analysis, the average WSS at PR site was significantly higher than that of non-PR site (18.7 (7.2–35.1) vs. 13.9 (5.2–30.3) Pa, p<0.001). The incidence of L-PR, C-PR, and others were 51%, 42%, and 7%, respectively. In the L-PR, the peak WSS was most frequently observed in the lateral site (66.7%), whereas that in the C-PR was most frequently observed in the center site (70%) (Figure. 3). In the L-PR, the peak WSS value was significantly lower (44.6 (19.6–65.2) vs. 84.7 (36.6–177.5) Pa, p<0.001), and the thickness of broken fibrous cap was significantly thinner (40 (30–50) vs. 80 (67.5–100) μm, p<0.001), and the lumen area at peak WSS site was significantly larger than those of C-PR (1.5 (1.3–2.0) vs. 1.4 (1.1–1.6) mm2, p=0.008). Multivariate analysis demonstrated that the presence of peak WSS at lateral site, thinner broken fibrous cap thickness, and larger lumen area at peak WSS site were independently associated with the development of the L-PR.

Conclusions

A combined approach with CFD simulation and morphological plaque evaluation by using OCT might be helpful to predict future ACS events induced by PR.

Funding Acknowledgement

Type of funding source: None

Impact of left atrial appendage morphology on the silent cerebral infarction after cryoballoon ablation for atrial fibrillation

Aims

Cryoballoon ablation (CBA) is effective for atrial fibrillation (AF), however acute silent cerebral infarction (SCI) is not uncommon after CBA. This study aimed to clarify the relationship between the morphology of LAA and SCI.

Methods and results

From 2015 to 2019, 207 consecutive patients (65.1±11.4 years, 26.6% of female, 31.4% of persistent AF) who underwent CBA for AF at our hospital were enrolled. All patients were evaluated with computed tomography for LAA before CBA and divided into two groups as chicken wing (CW) group and non-CW group. SCI was evaluated with magnetic resonance imaging at the following day after CBA. As a result, 18.4% of patients have occurred SCI after CBA. Although the patients' background didn't differ between the two groups, the Hounsfield scale (LAA/Aorta ratio) was lower (non-CW vs. CW = 0.68±0.12 vs. 0.73±0.11, p=0.004), and LAA orifice size tended to be larger (16.9±4.6 vs. 15.8±4.1, p=0.053) in non-CW group. SCI significantly occurred in non-CW group (29.5% vs. 11.6%, p=0.003), especially in cauliflower shape of 45.0%. In multivariate analysis, non-CW (p=0.002, Odds ratio 3.2, 95% of CI 1.5–7.0), skipped DOAC before CBA (p=0.04, Odds ratio 6.1, 95% of CI 1.1–115.4), and touch-up ablation in left atrium (p=0.02, Odds ratio 2.8, 95% CI 1.2–6.5) were independent predictors of SCI.

Conclusions

SCI was not rare after CBA for AF. Morphology of LAA was strongly associated with SCI.

Funding Acknowledgement

Type of funding source: None

Morphological plaque characteristics and clinical outcomes of acute coronary syndrome patients with a cancer history

Background

Although previous studies have reported that patients with a history of cancer have 2–3 times higher risks for acute coronary syndrome (ACS), morphological culprit plaque characteristics in ACS patients with a cancer history and their relations with clinical outcomes remain unknown.

Methods

The Kobe University ACS-OCT registry is a multi-center registry of consecutive ACS patients who underwent OCT-guided emergent PCI in Japanese four centers. All patients were categorized into the patients without a history of cancer (non-cancer), those with a history of cancer who diagnosed more than one year before ACS (historical), and those with ongoing cancer treatment or diagnosis within one year before ACS (current). ACS culprit lesions were classified into plaque rupture (PR), plaque erosion (PE), and calcified nodule (CN) according to morphological features by OCT and clinical events were collected after the onset of ACS.

Results

Among 436 patients, 63 patients (14.4%) had a history of cancer or ongoing treatment of cancer (cancer patients). Cancer patients were significantly older than non-cancer patients (73.4±9.4 vs. 66.9±12.9, p=0.001), and non-ST segment elevation ACS was more frequently observed in cancer patients than in non-cancer patients (57.1% vs. 43.2%, p=0.039). Regarding the ACS culprit lesion, the frequency of PR was significantly lower and the frequencies of PE and CN were significantly higher in the cancer patients than in the non-cancer patients (Figure A1). The cumulative incidence of major adverse cardiovascular event (MACE: composite of cardiac death, non-fatal myocardial infarction, and any revascularization, stroke, and heart failure with admission) after the onset of ACS in cancer patients was significantly higher than that in the non-cancer patients (Figure B1). When the cancer patients were categorized into the historical and the current cancer patients, the frequency of PE was higher in the current and the historical cancer patients than the non-cancer patients. Also, the incidence of CN was significantly higher in the historical cancer patients than others (Figure A2). The cumulative incidence of MACE was significantly higher in the current cancer patients, followed by historical and non-cancer patients (Figure B2). Cox regression analyses demonstrated that the non-PR lesion (hazard ratio (HR) 0.65, 0.46–0.94, p=0.021), patients with multivessel disease (HR 2.55, 1.79–3.64, p<0.001), older patients (HR 1.02, 1.00–1.03, p=0.043) were independently associated with MACE after ACS. Moreover, multivariate analysis demonstrated that cancer history (HR 4.64, 2.34–9.21, p<0.001) and non-ST segment elevation ACS (HR 0.66, 2.34–9.21, p=0.038) were independently associated with non-PR lesion.

Conclusions

The present study revealed the difference in morphological plaque characteristics between cancer and non-cancer patients, which might explain potential underlying mechanisms for worse outcomes in cancer patients.

Funding Acknowledgement

Type of funding source: None

Design and synthesis of dual active neovibsanin derivatives based on a chemical structure merging method

A hybrid compound consisting of neovibsanin and trans-banglene was designed according to a structure merging method and synthesized via a sequence of key steps including a Diels-Alder cycloaddition, stereoselective alkynylation, and intramolecular oxa-Michael addition reaction. The biological activity of the synthetized acetal compound and its hemiacetal analogue was investigated in PC12 cells. These studies revealed that the designed hybrid compounds displayed neuritogenic activity. Furthermore, a relatively strong neurite outgrowth promoting activity was observed in the presence of NGF. These results suggest that the designed hybrid compound exhibited a dual activity.

Metabolite Profiling of Javanese Ginger Zingiber purpureum and Identification of Antiseizure Metabolites via a Low-Cost Open-Source Zebrafish Bioassay-Guided Isolation

The rhizomes of Zingiber purpureum, "Bangle", were investigated for its antiseizure properties using a streamlined and cost-effective zebrafish screening strategy and a mouse epilepsy assay. Its hexane extract demonstrated strong antiseizure activity in zebrafish epilepsy assay and was, therefore, selected for bioactivity-guided fractionation. Twelve compounds (1-12) were isolated, and two bioactive phenylbutenoids, trans- (11) and cis-banglene (12), reduced up to 70% of pentylenetetrazole (PTZ)-induced seizures. These compounds showed moderate activity against PTZ-induced seizures in a mouse epilepsy assay. To understand the specificity of Z. purpureum active compounds, its chemical profile was compared to that of Z. officinale. Their composition was assessed by differential metabolite profiling visualized by a molecular network, which revealed only vanillin derivatives and terpenoids as common metabolites and gave a comprehensive view of Z. purpureum composition. This study demonstrates the efficacy of a streamlined zebrafish epilepsy assay, which is therefore suitable for routine screening in phytochemistry laboratories.

The search for, and chemistry and mechanism of, neurotrophic natural products

Abstract

Neurotrophic factors, now termed neurotrophins, which belong to a class of polypeptidyl agents, have been shown to potentially be beneficial for the treatment of neurodegenerative diseases such as Alzheimer’s disease, because endogenous neurotrophic factors (NGF, BDNF, NT3, NT4) have been recognized to play critical roles in the promotion of neurogenesis, differentiation, and neuroprotection throughout the development of the central nervous system. However, high-molecular weight proteins are unable to cross the blood–brain barrier and are easily decomposed by peptidase under physiological conditions. To address this issue, small molecules that can mimic the functions of neurotrophic factors would be promising alternatives for the treatment of neurodegenerative disease. We have continued to search for natural products having typical neurotrophic properties, which can cause neurogenesis, enhance neurite outgrowth, and protect neuronal death using three cellular systems (PC12, rat cortical neurons, and MEB5 cells). In this review, we summarize the neurotrophic activities and synthesis of dimeric isocuparane-type sesquiterpenes from the liverwort, Mastigophora diclados, the mechanism of neurotrophic neolignans, magnolol, honokiol and their sesquiterpene derivatives, and introduce unique neurotrophin-mimic natural products, including seco-prezizaane-type sesquiterpenes from the Illicium species, vibsane-type diterpenes from Viburnum awabuki, and miscellaneous natural products with neurotrophic effects discovered by us.

Graphic abstract

Indonesian Ginger (Bangle) Extract Promotes Neurogenesis of Human Neural Stem Cells through WNT Pathway Activation

Indonesian ginger (Zingiber purpureum Rosc.), also known as Bangle, exhibits neurotrophic effects on cultured murine cortical neurons and in the adult mouse brain, but the underlying mechanisms remain unknown. Here, using human fetal neural stem cells (hfNSCs) as a model system for in vitro human neurogenesis, we show that Bangle extracts activate canonical WNT/β-catenin signaling. Bangle extract-treatment of hfNSCs not only promoted neuronal differentiation, but also accelerated neurite outgrowth from immature neurons. Furthermore, Bangle extracts induced expression of neurogenic genes and WNT signaling-target genes, and facilitated the accumulation of β-catenin in nuclei of hfNSC. Interestingly, altered histone modifications were also observed in Bangle-treated hfNSCs. Together, these findings demonstrate that Bangle contributes to hfNSC neurogenesis by WNT pathway and epigenetic regulation.

Chemistry and Neurotrophic Activities of (-)-Talaumidin and Its Derivatives

(–)-Talaumidin (1), a 2,5-biaryl-3,4-dimethyltetrahydrofuran lignan isolated from Aristolochia arcuata Masters, exhibits significant neurite-outgrowth promotion and neuroprotection in primary cultured rat cortical neurons and in NGF-differentiated PC12 cells. The first enantioselective total synthesis of 1 was achieved by a flexible and reliable synthetic pathway involving an Evans asymmetric aldol reaction, as well as a stereocontrolled hydroboration and Friedel–Crafts arylation, to construct the four contiguous chiral centers on the tetrahydrofuran (THF) ring of 1. In order to investigate the stereochemistry–activity relationship of 1, a systematic synthesis of all diastereomers of 1 was accomplished by applying the synthetic strategy used for natural product 1. The evaluation of neurite-outgrowth promotion by all of the synthesized diastereomers indicated that the (–)-(1S,2R,3S,4R)-isomer 1e was significantly more active than naturally occurring 1. Additionally, we established a synthetic methodology for talaumidin derivatives that could be used to prepare a variety of analogs in a few steps and on a large scale. The synthesized racemic analog rac-1e (56a) exhibited neurite-outgrowth promoting activity in NGF-differentiated PC12 cells to the same degree as the optically active (–)-1e, revealing that a relative configuration bearing all-cis- substituents is important for potent neurotrophic activity, whilst the absolute configuration does not affect activity. Fourteen analogs based on (±)-56a were prepared via the same synthetic methodology. Among them, 56b with a methylenedioxy group on both benzene rings was found to exhibit the most significant neurite outgrowth promotion. In addition, 56a and 56b induced regeneration of the mouse optic nerve in vivo, and their activity was higher than that of talaumidin, as well as their in vitro measured activity. Furthermore, the structure–activity relationship of 56b indicated that the two benzene rings were essential structures, and that the methyl groups on the THF ring could enhance the neurotrophic activity. This result suggests that the two benzene rings of the talaumidin derivatives are essential structures for neurotrophic activity, while the two methyl groups on the THF ring can enhance neurite-outgrowth activity. Finally, it was observed that 1 and derivatives 56a and 56b exhibited potent regenerative activity in the injured mouse optic nerve in vivo.

Jiadifenolide induces the expression of cellular communication network factor (CCN) genes, and CCN2 exhibits neurotrophic activity in neuronal precursor cells derived from human induced pluripotent stem cells

Jiadifenolide has been reported to have neurotrophin-like activity in primary rat cortical neurons, and also possesses neurotrophic effects in neuronal precursor cells derived from human induced pluripotent stem cells (hiPSCs), as we have previously reported. However, the molecular mechanisms by which jiadifenolide exerts its neurotrophic effects in rat and human neurons are unknown. Thus, we aimed to investigate the molecular mechanisms and pathways by which jiadifenolide promotes neurotrophic effects. Here, we found that jiadifenolide activated cellular communication network factor (CCN) signaling pathways by up-regulating mRNA level expression of CCN genes in human neuronal cells. We also found that CCN2 (also known as connective tissue growth factor, CTGF) protein promotes neurotrophic effects through activation of the p44/42 mitogen-activated protein kinase signaling pathway. This is the first discovery which links neurotrophic activity with CCN signaling.

P1912Incidence of silent cerebral thromboembolism in catheter ablation for atrial fibrillation under the use of DOAC: Comparison of cryoballoon versus radiofrequency ablation system

Background

Silent cerebral thromboembolism (CE) in catheter ablation for atrial fibrillation (AF) is not rare. Prior our study has reported lower incidence of silent CE in AF radiofrequency (RF) ablation using irrigated-tip catheter than conventional 4 or 8mm-tip catheter. In addition, the incidence of silent CE in AF ablation under direct oral anticoagulant (DOAC) was equivalent to continuous therapeutic warfarin. Recently pulmonary vein isolation (PVI) using cryoballoon (CB) has emerged as an alternative technique to RF ablation because some studies suggested that the efficacy for PVI by CB was equivalent to RF. However, incidence of silent CE in CB ablation under the use of DOAC is unknown.

Objective

We aimed to evaluate the incidence new silent CE in AF ablation using CB system compared with irrigated RF system under the use of DOAC.

Methods

322 consecutive patients with paroxysmal or persistent AF (155 using CB system, 167 using RF system) who underwent the first AF ablation were taking DOAC more than one month prior to the procedure. Throughout AF ablation procedure, heparin was administered to maintain activated clotting time (ACT) between 300 and 400 seconds. Head MRI was performed in all patients within 24 hours after the procedure.

Results

In 14 (9.0%) patients using CB and in 20 (12.0%) patients using RF, head MRI showed new embolic lesions without neurological symptom (P=0.469). Although the amount of heparin during the procedure in group CB was significantly less than in group RF (16134±3125 U vs. 18689±5222 U; P<0.0001), amount of heparin per hour in group CB was more than in group RF (8335±1955 U/h vs. 6143±1918 U/h; P<0.0001) because procedure time in group CB was shorter than in group RF (121.3±34.1 min vs. 189.5±47.4 min; P<0.0001). Mean ACT in both groups was maintained high level (3367±25.3 sec. vs. 338.6±23.5 sec.; P=0.479). In univariate analysis, minimum ACT during procedure, as before puncture of interatrial septum, were significantly correlated with the incidence of silent CE (P=0.027).

Conclusions

The incidence of silent CE in AF ablation using CB system was lower than RF system, although it was not a significant difference between different ablation techniques for AF. In AF ablation, the use of CB may be preferred rather than RF as ablation system in regard to risk reduction of thromboembolic complications.

Serine protease inhibitors and activators from Dalbergia tonkinensis species

The vulnerable plant Dalbergia tonkinensis Prain is a rare species in Vietnam. In the course of our studies on biologically active plants, we performed serine protease enzyme screenings. The results suggest that at concentrations of 25-250 ng/mL, methanol extracts of leaf and root, root ethanol extract and its dichloromethane fraction, and heartwood water decoction extract can serve as useful sources to stimulate trypsin enzyme activity. In addition, water decoction extracts of leaf and stem bark may explain unknown ethno-pharmacology due to the high inhibitory effects in enzyme assays using trypsin, chymotrypsin, and elastase. Among 23 isolated compounds and two semi-synthetic derivatives tested, quercetin (17) inhibits the activities of trypsin and chymotrypsin with IC₅₀ 9.7 µM. Flavonoids categorized as flavanone, isoflavanone, flavone, isoflavone, pretocarpan, aurone, and neoflavanone demonstrated variable activities. Several substitutions are closely correlated with protease actions, including hydroxylation at C-3 and C-3' in flavone and C-5 and C-3' in isoflavone, hydroxylation at C-3, C-5 and C-3', carboxylation at C-6 and C-8, and 7-substitution in flavanone; 7-substitution and methoxylation at C-3' in isoflavanone; and lactone ring opening in neoflavanone. In the assessment of casein cleavage, at a dose of 25 ng/mL, leaf water decoction extract demonstrates an inhibitory effect on casein cleavage by trypsin, whereas ethanol and methanol extracts of the root caused activation.

Safety Assessment of Bangle (Zingiber purpureum Rosc.) Rhizome Extract: Acute and Chronic Studies in Rats and Clinical Studies in Human

Bangle (Zingiber purpureum Rosc.) rhizome extract (BRE) contains phenylbutenoid dimers (banglenes), which exert neurotrophic effects and possess the potential capability to regenerate hippocampal neurons in mice. The acute and chronic oral toxicities of BRE powder were evaluated in Sprague-Dawley rats. A dose of BRE powder was estimated to be higher than 2000 mg/kg containing BRE 534 mg/kg as minimum lethal dose in a single-dose oral toxicity study. The no-observed-adverse-effect-level for the BRE powder was 1000 mg/kg/day (BRE 267 mg/kg) in the 90 day oral toxicity study. Four week clinical studies of BRE tablets in humans suggested that the ingestion of BRE tablets within 850 mg/man/day (BRE 227 mg/man/day) was safe for at least 1 month and in a usual manner. The C _max, t _max, and AUC of cis- and trans-(E)-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-enes (c- and t-banglenes) were calculated after the ingestion of BRE tablets (BRE 227 mg) and were 17.73 and 22.61 ng/mL, 1.8 and 1.8 h, and 71.47 and 95.53 ng/mL/h, respectively.

Antimicrobial Activity of the Constituents of Dalbergia tonkinensis and Structural-Bioactive Highlights

The vulnerable plant Dalbergia tonkinensis Prain, is a rare species, native to Vietnam. Phytochemical investigations and biological evaluations of this species are quite limited. Antimicrobial screening has suggested that, at the low dose of 1.0 mg/mL, the methanol extracts of the leaf, stem bark, and root, as well as chloroform fraction of heartwood can serve as useful sources against seven gram-positive skin microbacteria, Bacillus cereus (ATCC27522), Escherichia coli (JM109), Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (ATCC14990), Streptococcus pneumonia (ATCC49619), Streptococcus pyogenes (ATCC12344), and Vibrio parahaemolyticus (RIMD2210010), and four oral gram-positive microbacteria Streptococcus mutans (ATCC 25175), Streptococcus mitis (ATCC903), Streptococcus sobrinus (ATCC 33478), and Porphyromonas gingivalis (ATCC33277), with an inhibitory percentage of 60-80% growth for several strains Bacillus cereus, Escherichia coli, and Streptococcus pneumonia. We further assessed antimicrobial activities of the enriched diverse flavonoids from chloroform fraction of its heartwood. Extensive structural activity relationship studies showed structure function closely related to the antimicrobial activity, in which methoxylation at C-2’, and 4’ in isoflavanones, hydroxylation at C-3’ in flavones, substitution at C-5 in isoflavones, and lactone opened ring in neoflavonoids were found to increase the effective inhibitions. In the second antimicrobial assessment, the isolated flavonoid liquiritigenin showed the MIC values of 50, and 100 μg/mL against the microbacterial strains Staphylococcus aureus subsp. aureus (ATCC 11632), and Aspergillus niger (439), respectively, whereas the MIC value of 100 μg/mL was assignable to biochanin A against microbacterium Staphylococcus aureus subsp. aureus.

Sucupiranins A-L, Furanocassane Diterpenoids from the Seeds of Bowdichia virgilioides

Twelve new furanocassane diterpenoids, sucupiranins A-L (1-12), and three known compounds (13-15) were isolated from the seeds of Bowdichia virgilioides. The structures of the compounds were elucidated via ¹H and ¹³C NMR analysis, including 2D NMR (¹H-¹H COSY, HSQC, HMBC, and NOESY); HRMS data; and X-ray crystallographic analysis. The absolute configurations were defined using their electronic circular dichroism (ECD) spectra by applying the exciton chirality method to the bis-p-bromobenzoate of compound 13. Sucupiranin J (10) inhibited lipopolysaccharide-induced nitric oxide production (IC₅₀ 30.6 μM), whereas sucupiranins J (10), K (11), and 13 exhibited weak antimalarial activity against Plasmodium falciparum K1 with IC₅₀ values of 32.2, 23.5, and 22.9 μM and selectivity indices of 4.3, 1.9, and >12.0 (MRC-5/K1), respectively.

Three New Bibenzyls from the Twigs of Smilax longifolia

Three new bibenzyl compounds, 1-3, were isolated along with the previously known bibenzyls 4-6, one diarylpropanoid 7, and three diarylheptanoids 8-10 from the twigs of Smilax longifolia. The structures of the new compounds were elucidated by analyzing their spectroscopic data and comparing them with those of known compounds. Diarylheptanoid 9 exhibited potent lethality in the brine shrimp lethality test (BST).

Two New Carboxyethylflavanones from the Heartwood of Dalbergia tonkinensis and Their Antimicrobial Activities

Two new carboxyethylflavanone derivatives, (2 S)-8-carboxyethylnarigenin (2) and (2 S)-6,8-dicarboxyethylpinocembrin (3) were isolated from the heartwood of Dalbergia tonkinensis Prain, along with four known compounds 1, and 4-6. The chemical structures of two new compounds 2 and 3 were elucidated based on analyses of the spectroscopic data, including 1D and 2D NMR, HR-ESI-MS, IR, UV, and CD spectroscopies. By carrying out antimicrobial assay, CH3OH and CHCl3 fractions exhibited weak MIC value at 200 μg/mL against filamentous fungus A. niger (439), whereas the known flavanone 1 and the new carboxyethylflavanone 2 had MIC at 100 μg/mL.

Construction of Canthin-5,6-diones via Termolecular Condensation Reaction: Studies on Synthesis of Amarastelline A

A termolecular condensation reaction of harmane, alkyl halide, and dimethyl oxalate has been developed for the construction of a variety of canthin-5,6-diones. The carbon skeleton of amarastelline A, a fluorescent canthin alkaloid, was synthesized in 99.8% yield by applying this procedure.

Studies on Extraction Conditions to Increase the Content of Neurotrophic Compounds in the Bangle (Zingiber purpureum) Extract

To develop the Javanese ginger Bangle ( Zingiber purpureum), which contains neurotrophic phenylbutenoid compounds named banglenes 1 and 2, as a functional food additive for protection of neurodegenerative disease, we investigated conversion method from 3 to 1 and 2 under practical conditions available in food processing steps. After several trials, we found that dimerization of 3 proceeded smoothly under refluxing EtOH/H2O (1/3) in the presence of ubiquinone (0.1 eq) in sealed tube, giving rise to 1 and 2 in 54% yield. When this condition was applied for 70% EtOH extract of bangle, content of 1 and 2 in the extract was increased 2-fold by 2.1%.

Chemical Constituents from Hericium erinaceus Promote Neuronal Survival and Potentiate Neurite Outgrowth via the TrkA/Erk1/2 Pathway

Hericium erinaceus is a culinary-medicinal mushroom used traditionally in Eastern Asia to improve memory. In this work, we investigated the neuroprotective and neuritogenic effects of the secondary metabolites isolated from the MeOH extract of cultured mycelium of H. erinaceus and the primary mechanisms involved. One new dihydropyridine compound (6) and one new natural product (2) together with five known compounds (1,3-5,7) were obtained and their structures were elucidated by spectroscopic analysis, including 2D NMR and HRMS. The cell-based screening for bioactivity showed that 4-chloro-3,5-dimethoxybenzoic methyl ester (1) and a cyathane diterpenoid, erincine A (3), not only potentiated NGF-induced neurite outgrowth but also protected neuronally-differentiated cells against deprivation of NGF in PC12 pheochromocytoma cells. Additionally, compound 3 induced neuritogenesis in primary rat cortex neurons. Furthermore, our results revealed that TrkA-mediated and Erk1/2-dependant pathways could be involved in 1 and 3-promoted NGF-induced neurite outgrowth in PC12 cells.

Anti-biofilm and bactericidal effects of magnolia bark-derived magnolol and honokiol on Streptococcus mutans

Dental caries affects people of all ages and is a worldwide health concern. Streptococcus mutans is a major cariogenic bacterium because of its ability to form biofilm and induce an acidic environment. In this study, the antibacterial activities of magnolol and honokiol, the main constituents of the bark of magnolia plants, toward planktonic cell and biofilm of S. mutans were examined and compared with those of chlorhexidine. The minimal inhibitory concentrations of magnolol, honokiol and chlorhexidine for S. mutans were 10, 10 and 0.25 µg/mL, respectively. In addition, each agent showed bactericidal activity against S. mutans planktonic cells and inhibited biofilm formation in a dose- and time-dependent manner. Magnolol (50 µg/mL) had greater bactericidal activity against S. mutans biofilm than honokiol (50 µg/mL) and chlorhexidine (500 µg/mL) at 5 min after exposure, while all showed scant activity against biofilm at 30 s. Furthermore; chlorhexidine (0.5-500 µg/mL) exhibited high cellular toxicity for the gingival epithelial cell line Ca9-22 at 1 hr, whereas magnolol (50 µg/mL) and honokiol (50 µg/mL) did not. Thus; it was found that magnolol has antimicrobial activities against planktonic and biofilm cells of S. mutans. Magnolol may be a candidate for prevention and management of dental caries.

Six New Triterpenoids from the Aerial Parts of Maytenus diversifolia

Five new ursane-type triterpenoids 1-5, and one new oleanane-type triterpenoids 7 were isolated from the MeOH extract of the aerial parts of Maytenus diversifolia. Their structures were elucidated by analyzing spectroscopic data and chemical transformation. Compounds 3 and 5 exhibited significant lethal activity in the brine shrimp lethality test (BST).

Six New Triterpenoids from the Aerial Parts of Maytenus diversifolia

Five new ursane-type triterpenoids 1-5, and one new oleanane-type triterpenoids 7 were isolated from the MeOH extract of the aerial parts of Maytenus diversifolia. Their structures were elucidated by analyzing spectroscopic data and chemical transformation. Compounds 3 and 5 exhibited significant lethal activity in the brine shrimp lethality test (BST).

A New Pimarane-type Diterpenoid from the Seeds of Bowdichia virgilioides

A new pimarane-type diterpenoid, sucupiol (1), and nine known furanocassane-type diterpenoids, vouacapane (2), 7β-hydroxyvouacapane (3), 7β-acetoxyvouacapane (4), 6α-hydroxyvouacapane (5), 6α-acetoxyvouacapane (6), sucutinirane F (7), sucutinirane E (8), 6α, 7β-diacetoxyvouacapane (9), and 6α, 7β-diacetoxyvouacapane-14β-al (10), were isolated from the seeds of Bowdichia virgilioides and their structures were elucidated by using 2D NMR data. The isolation of 1 provides evidence to support the presence of intermediate A in the course of biosynthesis of furanocassane-type diterpenoids.

A New Pimarane-type Diterpenoid from the Seeds of Bowdichia virgilioides

A new pimarane-type diterpenoid, sucupiol (1), and nine known -furanocassane-type diterpenoids, vouacapane (2), 7β-hydroxyvouacapane (3) 7β-acetox yvouacapane (4), 6α-hydroxyvouacapane (5), 6α-acetoxyvouacapane (6), sucutinirane F (7), sucutinirane E (8), 6α, 7β-diacetoxyvouacapane (9), and 6α, 7β-diacetoxyvouacapane-14β-al (10), were isolated from the seeds of Bowdichia virgilioides and their structures were elucidated by using 2D NMR data. The isolation of I provides evidence to support the presence of intermediate A in the course of biosynthesis of furanocassane-type diterpenoids.

Bangle (Zingiber purpureum) Improves Spatial Learning, Reduces Deficits in Memory, and Promotes Neurogenesis in the Dentate Gyrus of Senescence-Accelerated Mouse P8

Bangle (Zingiber purpureum) is a tropical ginger that is used as a spice in Southeast Asia. Phenylbutenoid dimers isolated from Bangle have exhibited neurotrophic effects in primary cultured rat cortical neurons and PC12 cells. Furthermore, chronic treatment with phenylbutenoid dimers enhances hippocampal neurogenesis in olfactory bulbectomized mice. In this study, we investigated the effects of Bangle extract on behavior and hippocampal neurogenesis in vivo. SAMP8 mice, which are an established model for accelerated aging, with age-related learning and memory impairments, were given a Bangle-containing diet for 1 month, and subsequent behavioral tests and immunohistochemistry for Ki67, a proliferating cell marker, were performed. We found that the Bangle-containing diet improved spatial learning and memory deficits in the Morris water maze and significantly increased the numbers of Ki67-positive cells in the dentate gyrus of the SAMP8 mice. In addition, the Bangle extract exhibited a neurotrophin-like activity as indicated by the induction of neurite sprouting in PC12 cells. Our results suggest that Bangle is beneficial for the prevention of age-related progression of cognitive impairment.